1. Field of the Invention
This invention relates to a printing apparatus having a conveying unit for medium.
2. Description of Related Art
Printing apparatuses of prior art may require to adjust a gap amount of a platen to a printing head, to switch distances as well as contacting or non-contacting between the pair of conveyance rollers, and to correct obliquely feeding of the medium, in order to perform printing media of various types such as continuous form sheets and single sheets with high quality Such a printing apparatus may be formed with the printing head mounted thereto and with a gap keeping roller mounted at a carriage travelable in a scanning direction, thereby the carriage pushing down the platen along a slope formed at each end of the platen on which the gap keeping roller travels to switch or adjust the gap amount of the platen to the printing head (see, e.g., Japanese Patent Application Publication No. 2005-231121 (A1)).
Another apparatus of prior art has been known as including two pairs of rollers for conveying a medium, a stopper for correcting obliquely feeding, or skew correction, of the medium, respective arms for rendering the roller pairs contacting or separating, an arm for opening and closing the medium conveyance route with the stopper, and cams of three types for rendering the respective arm pairs contacting or separating and for rendering the stopper opening and closing upon changing arm's positions, respectively, thereby performing switching of contacting or separating of the conveyance roller pair, correcting obliquely feeding of the medium, etc. (see, e.g., Japanese Patent Application Publication No. 2008-297076 (A1)).